High-temperature interband cascade lasers emitting at λ=3.6–4.3μm

The authors report the operating characteristics of ten-stage interband cascade lasers from two wafers with room-temperature wavelengths of 4.1 and 4.3μm. For 150-μm-wide stripes, the threshold current densities are as low as 4.8A∕cm2 at 78K (cw) and 1.15kA∕cm2 at room temperature (pulsed). At 78K, the cw wall-plug efficiency for an 11-μm-wide ridge with 0.5-mm-long cavity and coated facets is 27%, while a 3-mm-long cavity emits a maximum cw power of 200mW. Devices from the two wafers have maximum cw operating temperatures of 261K (λ≈4.0μm) and 243K (λ≈4.2μm).